Electrochemical synthesis and property characterisation of graphene oxide using water as electrolyte

Abstract Graphene oxide (GO) sheets were synthesized using tap water as the electrolyte in an electrochemical exfoliation method, that is cost-effective, environmentally friendly and relatively simple. The effects of electrode materials, i.e. carbon fibre sheets and graphite rod, and different intensities of electrical current on the final properties of GO were explored by UV-Vis spectroscopy, Raman spectroscopy, X-ray Photoelectron spectroscopy and transmission electron microscopy measurements. Experimental results showed that highly dispersed GO materials could be successfully prepared even when tap water was used as the electrode, thus avoiding any strong oxidative electrolytes. Furthermore, both the electrode materials and the different intensities of electrical current could influence the properties of the resulting GO materials. When the electrical current increased, the concentration of GO in water also increased with the formation of more defects and carboxyl groups (-O-C=O), but fewer epoxy or hydroxyl groups (-C-O) and a lower oxidation degree. Additionally, an increased current intensity led to the formation of smaller GO particles, with particle size range dependent on the electrodes. Carbon fiber sheets appear to be preferable for large-scale productions of GO due to more controllable size range, significantly higher concentration and fewer overlapped layers when compared to the graphite rods at a given electrical current.